A lentogenic NDV strain (La Sota) selectively infects proliferating cells. A Immunofluorescence analysis and quantification of NDV and BrdU staining in HeLa cells infected with the lentogenic NDV La Sota strain (0.1 MOI) and labeled with BrdU (5 μM) at 12 hpi. Scale bar, 20 μm. Data are presented as the mean ± SD of triplicate samples from three independent experiments. *P < 0.05 by t-test. B qRT-PCR analysis of NDV M gene expression normalized to β-actin expression in HeLa cells infected with different viral titers and treated with different concentrations of BrdU (0, 2, 5 and 10 μM). Data are presented as the mean ± SD of triplicate samples from four independent experiments. C Flow cytometry for cell cycle analysis of HeLa cells infected with NDV (0.1 MOI). D Fluorescein-labeled SNA and MAL1 were used to detect Sia expression on the surface of HeLa cells. E FACS analysis of HeLa cells colabeled with PI and either SNA or MAL1.